T-chord open web joist with adjustable ends

ABSTRACT

The disclosed device is directed towards a truss comprising an upper T-shaped chord. A lower T-shaped chord is coupled to said upper chord. A plurality of web members are coupled to said T-shaped chords. An extension section is coupled to said upper T-shaped chord and said lower T-shaped chord approximate the web. Said extension section is configured to by adjustable by trimming.

BACKGROUND

The present disclosure relates to the field of joist and trussconstruction. In particularly the disclosure relates to a broad spectrumof joist's or trusses having T-shaped chords with the benefits ofadjustable length.

Current joist designs offer different design types and can fall into twogeneral categories, open web truss or closed web joist. Both havedisadvantages for the consumer.

One type of conventional open web truss which is used for supportingbuilding floor and roof structures and the like is formed by twoparallel wooden chords, such as 2×4 or 2×3 dimensions, or the use ofcomposite lumber such as Laminated Veneer Lumber (LVL), arranged oneover the other interconnected by webs of steel or wood. The webs may beattached by gluing or by sheet metal connector plates having tampedteeth protruding out allowing them to embed into the wooden chords. Sucha truss is generally manufactured in a factory and transported to aconstruction site for installation as a component of the building. Thistype of truss is known in the art of trusses as an open web truss andhas the ability to be designed with the chord being oriented either inthe flat or wide direction or vertically or the narrow direction. Whilethe truss with the flat lumber suffers from not enough material forstrength the vertically assembled truss suffers from too narrow of anailing surface.

It is also known in the art of joist design to build a solid web joistconsisting of two parallel wooden chords connected by a continuous solidweb such as plywood or Oriented Strand Board (OSB). Such a joist suffersfrom having the solid web which doesn't leave any area for utilitiessuch as plumbing, electrical or duct work to pass through them.

There are current designs combining both features of the solid web joistand an open web truss. These combinations are limited in production dueto difficulty in manufacturing or to weaknesses due to lumberorientation.

Therefore there is a need for a joist that can combine the strength of asolid web joist with the capabilities of an open web truss and theflexibility of an adjustable length which prior art has not addressed.

SUMMARY

The disclosed device is directed towards a strong open web truss formedfrom an upper chord and a lower chord that are interconnected bydiagonal and/or vertical webs. The chords are T-shape providing strengthin the vertical direction and giving a wider nailing surface in thehorizontal direction. An extension portion is coupled to the upper chordand lower chord with a self-locking bulbous rabbet proximate the web ateach end allowing the length of the truss to be adjusted. Typically thetruss is assembled from wooden components.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the truss of the prescribed invention are shown indetail below with reference to attached drawings.

FIG. 1 is a partial elevation view of an exemplary truss.

FIG. 2 illustrates a complete isometric view of an exemplary truss.

FIG. 3 is a perspective view of a T-shaped chord.

FIG. 4 is a cross sectional end view of the T-shaped chord andconnection to the end adjustable block using a self-locking bulbousrabbet.

FIG. 5 is an exploded cross sectional view of the self-locking bulbousrabbet in detail.

DETAILED DESCRIPTION

Persons of ordinary skill in the art will realize that the followingdisclosure is illustrative only and not in any way limiting. Otherembodiments of the invention will readily suggest themselves to suchskilled persons having the benefit of this disclosure.

This disclosure describes a truss with T-shaped chords. The T-shapedchord includes a horizontal section connected to a vertical leg sectionapproximate the center of the horizontal section forming a T. The chordswill be interconnected by webs connected to the vertical section of theT-shaped chord. The truss includes extension sections at opposite endsof the chords. The extension sections extend beyond the webbing. Theextension sections are configured to be adjustable allowing for properfit upon installation of the truss. The extension sections generallyhaving an I-beam cross sectional shape. Particularities for theadjustable sections are described below in more specific detail.

FIG. 1 illustrates a partial elevation view of an exemplary truss. Thetruss 10 comprises an upper chord 21 combining a horizontal section 111with a vertical section 11A and a lower chord 21 combining a horizontalsection 11 with a vertical section 11A. In an exemplary embodiment, theupper and lower horizontal sections 11 can be made of solid lumber, suchas 2×3 or 2×4 lumber or from composite lumber such as Laminated VeneerLumber (LVL), GluLam, Laminated Strand Lumber (LSL) other types ofcomposite lumber. The vertical section 11A can be made of thinner lumbersuch as 1×3 or 1×4 or from the same thickness lumber as the horizontalsection 11 is made. The vertical section may be made of solid lumber orcomposite lumber such as Laminated Veneer Lumber (LVL), GluLam, orLaminated Strand Lumber (LSL) or other types of composite lumber. Theupper vertical section 11A is coupled with a strut or web 13 to thelower vertical section 11A. In an exemplary embodiment, the horizontalsections 11 and the vertical sections 11A may be comprised from a singlepart or from individual parts.

The web members 13 are generally arranged in a Warren or V type trusspattern. In another exemplary embodiment, the webs 13 may be arranged ina fan type arrangement where a vertical web 14 and a diagonal web 13intersect at the vertical chord section 11A. The web members 13, 14 maybe connected to the vertical section of the chord 11A by metal connectorplates or by finger type adhesive joints or by some other fashion. Theweb members 13, 14 may be comprised of solid lumber, composite lumber orby metal, either stamped sheet metal or tubular. It will be appreciatedby others in the art that other materials may be used while stillembodying the spirit of the present invention.

The adjustable truss 10 is constructed with an adjustable end block 12at each end having a bulbous tenon 16 machined on the top and bottomedge allowing it to lock itself into the vertical sections 11A. In theexemplary embodiment the truss 10 will have a similar bulbous rabbet 16machined into the vertical sections at the extension to accept theadjustable end block 12. The connection between the adjustable end blockwill be accomplished with glue. The adjustable end block 12 may becomprised of solid lumber or of composite lumber. The first web 13 maycomprise a Bulbous rabbet 16 on one edge to receive a bulbous tenon 17from one edge of the adjustable end block 12. Those skilled in the artwill appreciate that the bulbous tenon 17 and rabbet 16 is aself-locking connection and that it requires no clamping time forgluing, speeding up production time.

FIG. 2 illustrates a complete isometric view of the invention in anexemplary form. In this exemplary embodiment, truss 10 includes an upperchord 21 comprised of a horizontal section 11 with a vertical section11A and a lower chord 21 comprised of a horizontal section 11 with avertical section 11A. The upper chord 21 is interconnected to the lowerchord 21 by way of webs 13, 14 configured in a v-shape configurationwith multiple spans. An opening 15 approximate the center of the spancan be used to facility additional space needed for placement ofplumbing or duct work. The opening 15 can be facilitated by a web 14placed vertically at each end of the opening 15. In another alternativeexemplary truss, the web 14 maybe placed at the beginning of the webs 13and the adjustable end block 12. In this alternative embodiment thevertical web 14 may also include a bulbous rabbet 16 to receive thebulbous tenon 17. It will be appreciated by others skilled in the artthat other web configurations may be used.

FIG. 3 is an illustration of a perspective view of the T-shaped chord.The T-shape chord 21 will be comprised of a flat horizontal section 11and a vertical section 11A. In an alternative exemplary form, theT-shaped chord 21 may be comprised of a horizontal section 11 andmultiple vertical sections 11A. Those skilled in the art will recognizethat the T-shape offers strength in two directions, horizontally andvertically without the waste of using a larger solid piece of lumber andtherefore making more efficient use of our timber resources.

FIG. 4 is a cross sectional end view of the connection between thechords 21 and the adjustable end block 12. In the exemplary truss 10 thechords 21 are connected to the adjustable end block 12 with a bulbousrabbet 16 and tenon 17 and facilitated with an adhesive. The verticalsection 11A of the chord 21 will have a bulbous rabbet 16 at the end ofthe truss 10 to accept the bulbous tenon 17 of the adjustable end block12. An adhesive may be applied between the bulbous rabbet 16 and thebulbous tenon 17.

FIG. 5 illustrates an exploded cross sectional View of the connectionbetween the adjustable end block 12 and the chord 21. The chord 21comprised of the horizontal section 11 and the vertical section 11A. Thevertical section 11A having a bulbous rabbet 16 to accept the bulboustenon 17. The bulbous tenon 17 comprised of a bulbous end 20 tapers to anarrower neck 18 and a chamfered section 19. Likewise, the bulbousrabbet 16 comprised identically to accept the bulbous tenon 17.

1. A truss comprising: An upper chord having a T-shape; A lower chordhaving a T-shape coupled to said upper T-shaped chord; A web coupled tosaid upper T-shaped chord and said lower T-shaped chord. An extensionsection coupled to said upper T-shaped chord and said lower T-shapedchord proximate the web comprising an adjustable end block.
 2. The trussassembly of claim 1, wherein said upper chord has a T-shaped crosssection comprised of a horizontal section and a vertical section.
 3. Thetruss assembly of claim 1, wherein said lower chord has a T-shaped crosssection comprised of a horizontal section and a vertical section.
 4. Thetruss assembly of claim 1, wherein comprising an extension section ateach end with an adjustable end block.
 5. The T-shaped upper chord ofclaim 2, wherein said adjustable end block is connected by a bulbousrabbet and tenon.
 6. The T-shaped lower chord of claim 3, wherein saidadjustable end block is connected by a bulbous rabbet and tenon.
 7. Thetruss adjustable end block of claim 4, wherein said adjustable end blockhaving a bulbous tenon matching the bulbous rabbet of the T-shapedchords.
 8. The truss assembly of claim 1, wherein said extension sectionis configured to be trimmed.
 9. The truss assembly of claim 1, whereinsaid web is connected to an extension section by a bulbous rabbet andtenon.
 10. The truss adjustable end block of claim 4, wherein saidadjustable end block has a bulbous tenon matching the bulbous rabbet ofsaid web.
 11. A method of using a truss comprising; Providing a firststructural support configured to receive the truss and a secondstructural support configured to receive the truss, the truss comprisingan upper T-shaped chord, a lower T-shaped chord, a web coupled to saidupper T-shaped chord and said lower T-shaped chord, and a firstextension section coupled to said upper T-shaped chord and said lowerT-shaped chord proximate said web and a second extension section coupledto said upper T-shaped chord and said lower T-shaped chord oppositefirst extension section; Trimming said first extension section to couplewith said first structural support; Trimming said second extensionsection to couple with said second structural support.